Data exchange among computers can take the form of client-server communications, peer-to-peer communications, process-to-process communications, and the like. Some existing systems attempt to anticipate data queries to be received by one device from another device by pre-programming those data queries. Such systems, however, require significant resources and cannot anticipate every possible data query. Other existing systems allow devices to create imperative queries such as in the JAVASCRIPT scripting language. With these systems, however, queries are difficult to compose, serialize, and parse because of their length and syntactic complexity. Further, imperative queries expose security vulnerabilities at least because they contemplate the execution of code from untrusted sources (e.g., the performance of unrestricted allocation and copying). As such, these existing systems fail to prevent or contain the execution of malicious queries injected into communications sent over transport protocols such as the hypertext transfer protocol (HTTP).